Quantum Key Distribution (QKD or "quantum cryptography") uses single photons to offer a solution to the imminent problem of protecting data against security threats. It is based on fundamental laws of quantum physics and its inherent true randomness, and enables information-theoretically provable forward security, which is resilient against future advancements in computational attacks and even quantum computation. Since its first advent as a promising theoretical concept 30 years ago, a wide variety of different QKD protocols has emerged and been demonstrated in real-world communication networks. In this presentation, I will review this technology and give an overview over the latest developments. In particular, I will focus on the most recent QKD network in Columbus, and other networks as they are currently being installed all over the world.
